Manufacture of sulfite pulp from resinous woods.



circulation promoting the result.

UNITE STATES PATENT oEEIoE.

- OMA CARE, OF ASHEVILLE, NQRTH CAROLINA.

MANUFACTURE OF SULFITE PULP FROM RESINOUS WOODS.

No Drawing. I

To all whom it may concern Be it known that I, OMA CARR, a citizen of the United States of America, residing at Asheville, county of B'uncombe, State of North Carolina, have invented certain new and useful Improvementsin the Mannfacture of Sulfite Pulp from Resinous lVoods, of which the following specification is a clear description.

Practically all resin-bearing woods store the greater part of their resin in the summer ringof the wood, the rest being stored in the medullary rays. Vhere'ver the resins are stored the cellulose is stained yellow or yellow-brown. In many varieties of pine this stain is of such character that'it does not dissolve out under the action of the sulfite cook liquor, the stained fibers being only partially cooked and eventuall showing in the pulp as shieves or ye low shiners. These pines are not, therefore, available for pulp by the sulfite process in their naturaljstate; and as they are very abundant, of rapid growth, and of insignificant value for lumber or fuel use, it is economically desirable to render them suitable.

It is the object of my invention to attack the yellow ring, or stained fibers, before subjecting the wood to the sulfite cook, the desirable characteristics of which, as compared with the soda process, are well known. This I accomplish by the use of turpentine and alkali in combination. The resins causing the stain are complex in chemical composition, some being acid in nature and soluble in alkaline solvent, while others act as neutral resins and aresoluble in turpentine. r

An outline of one general method of procedure is as follows: The wood is chipped in the usual way and the chips placed in an autoclave (one of a series); they are then extracted by turpentine, a large part of the resins responding to this solvent, heat and Following the turpentine extraction I place on the chips a solution of alkali (common soda ash is convenient, but caustic soda is more effective), and by heat and circulation'remove the remaining resins. The extraction may be conducted with the autoclaves as a series, inter-connected, or intermittently, the alkali solvent may precede the turpentine, or, the

Specification of Letters Patent.

Application filed August 9, 1913.

obtained in the f free state. turpentine is COIltillIlQd in the wood prima- Patented Mar. 10, 1914;. Serial No. 733,900.

two solvents may be used together. the turpentine emulsifying with the alkali solvent. A specific procedure may be as follows: A battery, or' series, of autoclaves is employed, preferably eight in number and interconnected by appropriate pi ing and provided with heaters and valves. Klumbers one to six will contain chips submerged in alkaline solvent, numbers seven and eight chips submerged in turpentine solvent. By means of compressed air the solvent in number one is forced forward, a draw of alkaline solvent being taken from number six; simultaneously fresh turpentine solvent is forced into number seven and a draw of such solvent taken from number eight. Then number one is dumped of its charge of spent chips, and filled with fresh, or unextracted. chips. Number eight is now connected with number one, and by running fresh alkaline solvent into number two circu lation is forced through the battery and tur. pcntine solvent from number eight is forced over into number one, saturating the fresh chips there. The battery is now ready for compressed air in number two, a draw of alkaline solvent'from number seven; fresh turpentine solvent into number eight, and a draw of turpentine solvent from number one. Thus the extraction proceeds, the fresh chips being bathed in turpentine solvent and. the nearly spent chips bathed in alkaline solvent. The draw of alkaline solvent contains resins as soaps, and residual turpentine; the turpentine isrecovered by appropriate distillation, and by evaporation the resin soaps are obtained. The draw of turpentine solvent contains resins, and by distillation of the turpentine the resins are Whatever rily, is collected and appears in the turpentine reclaimed.

The spent chips are practically free of resin and yellow stain, and after draining or drying may be cooked by the conventional sulfite process.

Obviously the process may be reversed, the alkaline solvent preceding the turpentine solvent, while it is also apparent that the two solvents may be merged together; and it is further apparent that the extraction may be conducted in an intermittent manner instead of serially. The specific pro subjecting the wood chips to turpentineand 1O cedu re described above, however gives best also an alkaline solvent, and then cooking results. i Y the chips by the 'sulfite process. Having described my invention, what I In testimony whereof I hereunto a ffix my claim as new and desire to secure by Letsignature in the presence of two witnesses. ters Patent is: y OM-A CARR. I

lhe method herein described of making, Vitnesses:

' sulfite pulp from. resinous woods, consisting JOHN T. SMITH, J r.

in dissolying out the resinous matters by R. M. Ronnn'rs. 

